JP4512330B2 - Composite optical element and optical transceiver - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a composite optical element., AndRelated to optical transceivers.
[0002]
[Prior art]
In recent years, surface-emitting lasers have become increasingly useful as key devices for parallel optical interconnection. In its practical use, high mounting accuracy is required unlike conventional electric wiring. Therefore, a method for mounting an optical element using a member processed with extremely high precision by using a semiconductor process or the like and using the surface of the member as a reference surface has been studied. This highly processed member is called MOB (Micro-Optical Bench), and the mounting method using this MOB (MOB mounting method) is a very important technique for satisfying various requirements. This MOB mounting method also plays a major role in mounting a two-dimensional microlens array or the like. However, such a MOB mounting method still has a big problem in terms of manufacturing cost, and is particularly one of the biggest problems in electrical connection of a surface emitting laser and optical coupling with a microlens. .
[0003]
Thus, a method of directly attaching an element such as a microlens to a surface emitting laser substrate without using an MOB has been studied (for example, see Patent Document 1).
[0004]
[Patent Document 1]
JP 2002-31747 A
[0005]
[Problems to be solved by the invention]
However, an insulating resin such as polyimide is applied on the surface side of the substrate of the surface emitting laser by spin coating or the like in order to insulate the etched portion when forming the surface emitting laser, and the insulating resin is applied. The unevenness of the finished surface reaches several μm. For this reason, even if the optical element is directly mounted on the surface to which the insulating resin is applied, high mounting accuracy cannot be obtained.
[0006]
In addition, as a method for fixing the substrate of the surface emitting laser and the element substrate provided with the element, a method in which an adhesive is sandwiched between the substrate and the element substrate is also conceivable. However, due to variations in the thickness of the adhesive, It is difficult to achieve accuracy. The fixing method using a bump or the like similarly has an accuracy of several μm, and a problem remains.
[0007]
An object of the present invention is to increase the mounting accuracy with a simple configuration when various elements are mounted on a substrate of a surface emitting laser.
[0008]
Another object of the present invention is to perform high-precision bonding of a light transmission component such as an optical fiber to an element substrate with a simple configuration.
[0009]
[Means for Solving the Problems]
  The invention according to claim 1 is a composite optical element in which an element is mounted on a substrate of a surface emitting laser, wherein the substrateThe firstA first contact surface; a second contact surface that is a substrate surface of the element substrate on which the element is provided and is in contact with the first contact surface; the first contact surface and the second contact surface; An adhesive groove formed on at least one of the surfaces in contact with the surface, and the first contact surface and the second contact surface that are injected into the adhesive groove are positioned at the contact positions. And an adhesive that bonds and fixes the substrate and the element substrate.Then, an electrode groove is formed on the surface of the element substrate facing the substrate, and dicing is performed at the position of the electrode groove.It is characterized by that.
[0010]
Here, the “element” includes an element having various electrical, mechanical, and optical functions, and particularly indicates an element that is highly useful when mounted on a surface emitting laser. For example, electrical wiring, a cover for fixing or protecting a surface emitting laser, a member having a lens function, and the like are applicable.
[0011]
The “adhesive groove” may be formed on only one of the first contact surface and the second contact surface, or may be formed on both.
[0012]
  Therefore, the mounting of the element on the substrate of the surface emitting laser includes the first contact surface which is a part of the substrate surface of the substrate of the surface emitting laser, and the second contact surface which is a part of the substrate surface of the element substrate. The surface emitting laser substrate is fixed to the element substrate by injecting the adhesive into the adhesive groove and fixing the surface emitting laser substrate and the element substrate. Thereby, the substrate of the surface emitting laser and the element substrate can be fixed while maintaining the state in which the first contact surface of the surface emitting laser and the second contact surface of the element substrate are in contact with each other. The element is mounted on the substrate of the light emitting laser with an accurate and simple structure by removing error factors such as the thickness of the insulating resin layer covering the substrate surface of the surface emitting laser substrate and the thickness of the adhesive. be able to.In particular, the electrode groove is exposed by dicing after bonding the substrate having the surface emitting laser and the element substrate provided with the element, and wire bonding or the like can be performed with the electrode groove. When dicing so that the end surfaces of the substrate and the element substrate are shifted during dicing, the dicing stop position may be set within the height dimension of the electrode groove, and a highly accurate dicing stop position is required. Therefore, the workability of dicing work is improved.
[0013]
According to a second aspect of the present invention, in the composite optical element according to the first aspect, the first contact surface is an epitaxial surface, and the second contact surface is a polished surface.
[0014]
Here, the “epitaxial surface” is a surface formed by a chemical vapor deposition method, and is formed smoothly with high accuracy. The “polishing surface” is also formed smoothly with high accuracy.
[0015]
Therefore, since both the first contact surface and the second contact surface are formed smoothly with high accuracy, the fixed surface-emitting laser substrate and the element substrate are maintained in high parallelism, and the surface-emitting laser is maintained. The mounting accuracy of the element on the substrate becomes higher.
[0016]
According to a third aspect of the present invention, in the composite optical element according to the first or second aspect, the element is disposed on a surface side of the element substrate facing the surface emitting laser.
[0017]
Therefore, when an element is provided on the element substrate, the element is disposed on the side of the element substrate facing the surface emitting laser, thereby eliminating the influence of the thickness tolerance of the element substrate with respect to the distance between the element and the surface emitting laser. Thus, the tolerance of the distance between the element and the surface emitting laser can be reduced, and the mounting accuracy of the element with respect to the surface emitting laser is increased.
[0018]
According to a fourth aspect of the invention, in the composite optical element according to any one of the first to third aspects, the surface emitting laser and the element are arranged in an array.
[0019]
Therefore, in this composite optical element, the surface-emitting laser can be easily and accurately mounted on the substrate, and even when these surface-emitting lasers and elements are arranged in an array, each surface-emitting laser can emit light. The generated light becomes parallel light, thereby preventing the occurrence of crosstalk of light emitted from the adjacent surface emitting laser.
[0021]
Accordingly, the electrode groove is exposed by dicing after bonding the substrate having the surface emitting laser and the element substrate provided with the element, and wire bonding or the like can be performed by the electrode groove. When dicing so that the end surfaces of the substrate and the element substrate are shifted during dicing, the dicing stop position may be set within the height dimension of the electrode groove, and a highly accurate dicing stop position is required. Therefore, the workability of dicing work is improved.
[0022]
  Claim5The invention described in claim 1 to claim 14The composite optical element according to any one of the above, wherein the element is an electrical wiring.
[0023]
Accordingly, the mounting accuracy of the electric wiring on the substrate of the surface emitting laser is increased, and the energization to the surface emitting laser can be performed with high accuracy.
[0024]
  Claim6The invention described in claim 1 to claim 14The composite optical element according to any one of the above, wherein the element is a microlens.
[0025]
Therefore, the mounting accuracy of the microlens on the substrate of the surface emitting laser is increased, and the diffused light emitted from the surface emitting laser can be converted into parallel light with high accuracy. Furthermore, the mounting tolerance in the optical axis direction of the surface emitting laser can be increased by making the diffused light emitted from the surface emitting laser parallel by using a microlens as an element.
[0026]
As this microlens, a microlens formed by a photolithography process using a gray scale mask is preferable in that it can be formed into an arbitrary aspherical shape.
[0027]
  Claim7The described invention is claimed.6In the described composite optical element, the microlens includes a concave surface portion formed on the element substrate and a lens equivalent member having a refractive index larger than that of the element substrate filled so as to form a convex lens in the concave surface portion. It is characterized by that.
[0028]
Here, the light emitted from the surface emitting laser is diffused, and if the lens surface shape facing the diffused light is a convex shape, the incident angle becomes shallow and the reflectance becomes high. For this reason, the lens surface shape facing the surface emitting laser is preferably a concave shape. However, since the power is negative on the concave surface, the diffused light cannot be converted into parallel light. Accordingly, a concave surface portion is formed on the element substrate, and a lens-equivalent member having a refractive index higher than that of the element substrate, for example, a resin, is filled into the concave surface portion to form a functionally convex microlens. The surface facing the surface emitting laser in the lens equivalent member is preferably flat.
[0029]
Therefore, the reflectance when the light emitted from the surface emitting laser hits the microlens can be kept low, and a composite optical element with high light utilization efficiency can be obtained.
[0030]
  Claim8The invention described in claim 1 to claim 14The composite optical element according to any one of the above, wherein the element is a diffraction grating.
[0031]
Here, when a surface emitting laser is used for communication, it is necessary to selectively control the wavelength and perform multi-wavelength communication. At that time, there is a limit in correcting the chromatic aberration with respect to the difference in wavelength with a single microlens.
[0032]
Accordingly, the mounting accuracy of the diffraction grating on the substrate of the surface emitting laser is increased, and the light emitted from the surface emitting laser can be accurately emitted in any direction other than the optical axis. Further, by providing a diffraction grating as an element, a design that is resistant to chromatic aberration can be performed.
[0033]
Furthermore, the diffraction grating can be formed by a photolithography process, and can be formed simultaneously with the formation of the adhesive groove on the element substrate, thereby suppressing an increase in manufacturing cost.
[0034]
  Claim9The invention described in claim 1 to claim 18The composite optical element according to any one of the above, wherein a light transmission component is directly bonded to the element substrate.
[0035]
Here, “directly bonded” means that the positioning when the element substrate and the light transmission component are bonded is not performed by holding the element substrate or the light transmission component by the holding member, It means a state where the parts can be positioned by joining.
[0036]
Therefore, by directly joining the light transmission component and the element substrate, the light transmission component can be mounted with high accuracy without being affected by a manufacturing error included in the fixing member or the like as compared with the case where the light transmission component is fixed by the fixing member or the like. In particular, in the optical axis direction, since the light transmission component and the element substrate can be pressed and mounted, high mounting accuracy can be realized at low cost.
[0037]
  Claim10The described invention is claimed.9The composite optical element described above is characterized in that a resin is interposed between the light transmission component and the element substrate.
[0038]
Therefore, if there is an air layer between the light transmission component and the element substrate, reflection occurs at the end face of the light transmission component. However, the resin is interposed between the light transmission component and the element substrate. The difference in refractive index between the light transmission component and the reflectance decreases, and the optical coupling efficiency between the element substrate and the light transmission component increases.
[0039]
  Claim11The described invention is claimed.8Or9In the composite optical element described above, the light transmission component is an optical fiber, and a fixing groove into which the tip of the optical fiber is inserted is formed in the element substrate.
[0040]
Therefore, by inserting the tip of the optical fiber into the fixing groove, the optical fiber is prevented from shifting, and high mounting accuracy can be obtained at low cost.
[0041]
  Claim12The described invention is claimed.11In the composite optical element described above, a condensing lens is provided at the center of the fixed groove.
[0042]
Therefore, since the light incident on the optical fiber is collected by the condensing lens, even if the thickness dimension of the element substrate varies, the spot can be surely connected at the end face of the optical fiber, and the optical coupling efficiency Becomes higher.
[0043]
  Claim13The described invention is claimed.11Or12The composite optical element described above is characterized in that a taper portion whose diameter increases outward is formed at an edge portion of the fixed groove.
[0044]
Therefore, the optical fiber can be surely inserted into the fixed groove without providing play between the fixed groove and the optical fiber, and the tapered portion functions to guide the optical fiber inserted into the fixed groove to the center of the fixed groove. Therefore, the mounting accuracy of the optical fiber is increased.
[0045]
  Claim14The described invention is claimed.11Or13In the composite optical element according to any one of the above, a taper portion whose diameter is reduced toward the distal end side is formed at the distal end portion of the optical fiber.
[0046]
Therefore, the optical fiber can be surely inserted into the fixed groove without providing play between the fixed groove and the optical fiber, and the tapered portion functions to guide the optical fiber inserted into the fixed groove to the center of the fixed groove. Therefore, the mounting accuracy of the optical fiber is increased.
[0047]
  Claims13Claimed taper and claim14By providing the taper portion described above and making the taper angles substantially the same, the taper portion of the fixed groove and the taper portion of the optical fiber are in surface contact, and a more stable mounting state is obtained.
[0048]
  Claim15The optical transceiver of the described invention is claimed.10Or14A composite optical element directly bonded to the optical fiber, an LSI connected to the composite optical element, and an electrical connector connected to the LSI.
[0049]
  Therefore, the claims10Or14A low-cost optical transceiver can be provided by using the composite optical element in which the optical fibers according to any one of the above are directly joined.
[0056]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described with reference to FIG. The composite optical element 1 of the present embodiment is obtained by bonding and fixing an element substrate 4 provided with electric wirings 3 as elements to a semiconductor laser substrate 5 as a substrate provided with a surface emitting laser 2.
[0057]
  When forming the surface emitting laser 2HalfA clad layer, an active layer, and the like are formed by epitaxial growth on the conductor laser substrate 5 (details of the clad layer and the active layer are not shown), and the mesa 6 is formed by dry etching the formed clad layer and the like. . Thereafter, an insulating resin layer (polyimide) 7 is applied so as to cover the mesa 6 and the epitaxial surface exposed by dry etching (surface of one clad layer) through an electrode constriction process. The coated insulating resin layer 7 is subjected to a photocuring treatment through a mask. At this time, the light emitting region on the upper surface of the mesa 6 and the region where the element substrate 4 is brought into contact are not photocured and are made with an organic solvent. The insulating resin layer 7 is removed by washing. As a result, the epitaxial surface is exposed as the first contact surface 10 in the region where the element substrate 4 is in contact. Thereafter, the p-side electrode 8 is formed on the insulating resin layer 7, and the n-side electrode 9 is formed on the back surface of the semiconductor laser substrate 5.
[0058]
The element substrate 4 is a substrate formed of quartz, and a second contact surface 11 that is a substrate surface that contacts the first contact surface 10 of the surface emitting laser 2 in the element substrate 4 is a polishing surface. ing.
[0059]
When the second contact surface 11 is brought into contact with the first contact surface 10 of the semiconductor laser substrate 5 in order to adhere and fix the element substrate 4 to the semiconductor laser substrate 5, the element substrate 4 has a convex mesa 6. A recess 12 for avoiding a collision with the mesa 6 and an adhesive groove 13 are formed. These recesses 12 and adhesive grooves 13 are formed by a photolithography process. The adhesive groove 13 is formed in the area of the second contact surface 11 and is formed in a ring shape so as to surround the recess 12, and at least one portion extends to the end surface of the element substrate 4. It is an adhesive inlet.
[0060]
After the recesses 12 and the adhesive grooves 13 are formed, an aluminum film is deposited on the surface of the element substrate 4 where the recesses 12 and the adhesive grooves 13 are formed, and the aluminum film is patterned by a photolithography process. The electric wiring 3 which is an element is provided.
[0061]
The element substrate 4 is bonded and fixed to the surface emitting laser 2 by the following procedure. First, the first contact surface 10 of the surface emitting laser 2 is brought into contact with the second contact surface 11 of the element substrate 4. Positioning of the contact position at this time is performed while attaching an alignment mark (not shown) in each photolithography process in the surface emitting laser 2 and the element substrate 4 and observing the alignment mark with a microscope. Thereby, positioning accuracy on the order of several μm can be obtained. After the alignment is completed, the adhesive 14 is injected from the adhesive injection port. The injected adhesive 14 advances in the adhesive groove 13 by capillary action, and the surface emitting laser 2 and the element substrate 4 are bonded and fixed by the adhesive 14. The adhesive 14 is preferably of a type that is cured by ultraviolet irradiation.
[0062]
When the surface emitting laser 2 and the element substrate 4 are aligned, bumps 15 for connecting the p-side electrode 8 and the electric wiring 3 are interposed. The bump 15 is made of a material that can be easily deformed by applying pressure, and the contact state between the first contact surface 10 and the second contact surface 11 is maintained even when the bump 15 is interposed.
[0063]
By bonding and fixing the surface emitting laser 2 and the element substrate 4, the light emitting region of the upper surface portion of the mesa 6 is covered with the quartz element substrate 4, but the wavelength of the emitted light of the surface emitting laser 2 is in the 1.3 μm band. There is no problem because the quartz element substrate 4 is transparent to this wavelength.
[0064]
The composite optical element 1 formed by bonding and fixing the semiconductor laser substrate 5 provided with the surface emitting laser 2 and the element substrate 4 is attached to the submount substrate 16 for use. When the composite optical element 1 is attached to the submount substrate 16, the n-side electrode 9 and electrical wiring (not shown) on the submount substrate 16 are connected by the bumps 17, and the electrical wiring 3 and the submount substrate are connected. Connection with other electrical wirings (not shown) on 16 is made by bumps 18.
[0065]
In such a configuration, when mounting the electrical wiring 3 as an element on the semiconductor laser substrate 5 provided with the surface emitting laser 2, the first contact which is the epitaxial surface exposed by removing the insulating resin layer 7. The surface 10 and the second contact surface 11 which is the polishing surface of the element substrate 4 are brought into contact with each other, and the surface emitting laser 2 and the element substrate 4 are bonded and fixed by the adhesive 14 injected into the adhesive groove 13. . Therefore, the semiconductor laser substrate 5 and the element substrate 4 are fixed with the first contact surface 10 of the semiconductor laser substrate 5 and the second contact surface 11 of the element substrate 4 kept in contact with each other. The electrical wiring 3 can be mounted on the semiconductor laser substrate 5 with high accuracy and with a simple structure by removing error factors such as the thickness of the insulating resin layer 7, the bumps 15, and the adhesive 14. .
[0066]
In the present embodiment, the semiconductor laser substrate 5 provided with one surface emitting laser 2 and the element substrate 4 provided with one electrical wiring 3 corresponding thereto are bonded and fixed to one composite optical element 1. As an example, a wafer-like element in which a plurality of surface-emitting lasers 2 are provided in an array and a plurality of electrical wirings are provided in an array is described. A plurality of composite optical elements 1 as shown in FIG. 1 may be formed by forming a substrate, adhering and fixing the wafer-like laser substrate and the wafer-like element substrate with an adhesive, and separating them by dicing. .
[0067]
In this case, the step of adhering and fixing the wafer-shaped laser substrate and the wafer-shaped element substrate is performed by removing the insulating resin layer covering the substrate surface of the wafer-shaped laser substrate and exposing the substrate surface (first contact in FIG. 1). The contact surface 10) and the substrate surface of the wafer-like element substrate (corresponding to the second contact surface 11 in FIG. 1) are brought into contact with each other, and the adhesive formed on at least one of the contact surfaces of the substrate surfaces This is performed by injecting an adhesive into the agent groove (corresponding to the adhesive groove 13 in FIG. 1). It should be noted that the adhesive groove formation position can maintain the adhesive fixing state between the surface emitting laser substrate and the element substrate in each composite optical element (corresponding to the composite optical element 1 in FIG. 1) even after separation by dicing. Form in position.
[0068]
As a result, as compared with the case where the element substrate is bonded and fixed to the substrate of each surface emitting laser, the operation of bonding and fixing the wafer-shaped laser substrate and the wafer-shaped element substrate performed when forming the plurality of composite optical elements 1 Since only one time is required, the manufacturing cost is reduced.
[0069]
When the wafer-like laser substrate and the wafer-like element substrate bonded and fixed are separated by dicing, the dicing position on one end side is shifted between the semiconductor laser substrate 5 side and the element substrate 4 side as shown in FIG. The shifted portion can be used as a structure suitable for connection using the bumps 18.
[0070]
It is also effective to use a vacuum chamber (not shown) for the process of bonding and fixing the semiconductor laser substrate 5 and the element substrate 4 with the adhesive 14. In this case, the substrate surface (first contact surface 10) of the semiconductor laser substrate 5 and the substrate surface (second contact surface 11) of the element substrate 4 are brought into contact with each other, and the adhesive groove 13 is formed as an adhesive inlet. Close the part except for. The semiconductor laser substrate 5 and the element substrate 4 which are brought into contact with each other in this way are placed in a vacuum chamber and evacuated to create a vacuum in the vacuum chamber. At this time, an adhesive is applied to the end portions of the semiconductor laser substrate 5 and the element substrate 4 to temporarily fix them. The adhesive inlet is dipped in the adhesive filled in the dish in the vacuumed vacuum chamber, and then the vacuuming in the vacuum chamber is released. As a result, the adhesive in which the adhesive injection port is immersed is sucked into the adhesive groove 13 in a negative pressure state, and the adhesive groove 13 is performed when the semiconductor laser substrate 5 and the element substrate 4 are bonded and fixed. The adhesive 14 can be reliably injected into the substrate in a short time, and the workability of manufacturing the composite optical element 1 is improved.
[0071]
The alignment position of the semiconductor laser substrate 5 and the element substrate 4 is aligned with the observation mark with the microscope using the alignment mark attached to the semiconductor laser substrate 5 and the element substrate 4. After the rough aligns and removes from the vacuum chamber, it can be aligned with high accuracy. After highly accurate alignment, the adhesive 14 is cured by irradiating with ultraviolet rays.
[0072]
A second embodiment of the present invention will be described with reference to FIG. In addition, the same part as the part demonstrated in 1st Embodiment is shown with the same code | symbol, and description is also abbreviate | omitted (the following embodiment is also the same).
[0073]
The composite optical element 21 of the present embodiment is obtained by bonding and fixing an element substrate 4 provided with a microlens 22 as an element to a semiconductor laser substrate 5 provided with a surface emitting laser 2.
[0074]
The microlens 22 is formed on the surface of the element substrate 4 opposite to the surface facing the surface emitting laser 2. The surface of the element substrate 4 on which the microlenses 22 are formed is also polished in the same manner as the second contact surface 11, and the microlenses 22 are formed on the polished surfaces.
[0075]
The microlens 22 is disposed in front of the light emitted from the surface emitting laser 2 and is designed so that the diffused light emitted from the surface emitting laser 2 can be converted into parallel light. Further, the micro lens 22 is formed into an aspheric surface by a photolithography process using a gray scale mask, and the wavefront aberration of light can be reduced.
[0076]
The first and second contact surfaces (epitaxial surface) 10 of the semiconductor laser substrate 5 and the second contact surface (polishing surface) 11 of the element substrate 4 are in contact with the semiconductor laser substrate 5 and the element substrate 4 that are bonded and fixed. The tolerances are controlled with very high accuracy.
[0077]
The semiconductor laser substrate 5 and the element substrate 4 are bonded and fixed in the same manner as in the first embodiment. The first contact surface 10 of the semiconductor laser substrate 5 and the second contact surface 11 of the element substrate 4 are And an adhesive 14 is injected into the adhesive groove 13 formed in the second contact surface 11.
[0078]
Although illustration is omitted in the present embodiment, the electrical connection of the surface emitting laser 2 is performed in the same manner as in the first embodiment.
[0079]
In this configuration, the element substrate 4 is bonded and fixed to the semiconductor laser substrate 5 on which the surface emitting laser 2 is provided. The first contact surface 10 of the semiconductor laser substrate 5 and the second contact surface 11 of the element substrate 4 are used. It can carry out with maintaining the state which contacted. Since both the first contact surface 10 and the second contact surface 11 are surfaces formed with high precision and smoothness, the mounting of the microlens 22 as an element on the semiconductor laser substrate 5 is performed with the insulating resin layer 7 or It is possible to remove the error factors such as the thickness of the bump and the adhesive, and to perform with high accuracy and a simple structure.
[0080]
Also in this embodiment, as described in the first embodiment, a wafer-like laser substrate in which a plurality of surface emitting lasers 2 are provided in an array is formed, and a plurality of microlenses is further formed. As shown in FIG. 2, a wafer-like element substrate 22 is formed in an array, and the wafer-like laser substrate and the wafer-like element substrate are bonded and fixed with an adhesive, and then separated by dicing. A plurality of composite optical elements 21 may be formed. As a result, compared with the case where the element substrate is bonded and fixed to each surface emitting laser, the work of bonding and fixing the wafer-shaped laser substrate and the wafer-shaped element substrate performed when forming the plurality of composite optical elements 21 is one. The manufacturing cost can be reduced because it requires only one time.
[0081]
A third embodiment of the present invention will be described with reference to FIG. The composite optical element 31 of the present embodiment is obtained by bonding and fixing an element substrate 4 provided with a microlens 32 as an element to a semiconductor laser substrate 5 provided with a surface emitting laser 2, and has a basic structure. This is the same as the second embodiment.
[0082]
The difference between the present embodiment and the second embodiment is the position where the microlens 32 is formed. In this embodiment, the microlens 32 is formed on the surface of the element substrate 4 facing the surface emitting laser 2. ing.
[0083]
The microlens 32 is disposed in front of the light emitted from the surface emitting laser 2 and is designed so that the diffused light emitted from the surface emitting laser 2 can be converted into parallel light. The microlens 32 is formed together with the recess 12 and the adhesive groove 13 by a photolithography process.
[0084]
In such a configuration, the element substrate 4 is bonded and fixed to the semiconductor laser substrate 5 in a state where the first contact surface 10 of the semiconductor laser substrate 5 and the second contact surface 11 of the element substrate 4 are in contact with each other. This can be done while maintaining. Since both the first contact surface 10 and the second contact surface 11 are surfaces formed with high precision and smoothness, the mounting of the microlens 22 as an element on the semiconductor laser substrate 5 is performed with the insulating resin layer 7 or It is possible to remove the error factors such as the thickness of the bump and the adhesive, and to perform with high accuracy and a simple structure.
[0085]
Furthermore, since the microlens 32 is formed on the surface of the element substrate 4 facing the surface emitting laser 2, the microlens 32 and the surface emitting laser are not affected by the thickness tolerance of the element substrate 4 when the microlens 32 is mounted. 2 can be further reduced, and the mounting accuracy of the microlens 32 on the semiconductor laser substrate 5 can be further increased.
[0086]
Also in this embodiment, as described in the first embodiment, a wafer-like laser substrate in which a plurality of surface emitting lasers 2 are provided in an array is formed, and a plurality of microlenses is further formed. As shown in FIG. 3, a wafer-like element substrate 32 having an array 32 is formed, and the wafer-like laser substrate and the wafer-like element substrate are bonded and fixed with an adhesive, and then separated by dicing. A plurality of composite optical elements 31 may be formed. Thereby, compared with the case where the element substrate is bonded and fixed to the substrate of each surface emitting laser, the work of bonding and fixing the wafer-shaped laser substrate and the wafer-shaped element substrate performed when forming the plurality of composite optical elements 31 is performed. Since only one time is required, the manufacturing cost is reduced.
[0087]
A fourth embodiment of the present invention will be described with reference to FIG. The composite optical element 41 of this embodiment is obtained by bonding and fixing an element substrate 4 provided with a diffraction grating 42 as an element to a semiconductor laser substrate 5 provided with a surface emitting laser 2. The bonding and fixing structure between the element substrate 4 and the surface emitting laser 2 is the same as that in each of the above-described embodiments, and the diffraction grating 42 is surface-emitting in the element substrate 4 as in the microlens 32 of the third embodiment. It is formed on the surface facing the laser 2.
[0088]
The diffraction grating 42 is arranged on the front side of the light emitted from the surface emitting laser 2 and is designed so that the diffused light emitted from the surface emitting laser 2 can be emitted in any direction other than the optical axis. Yes. The diffraction grating 42 is formed by a photolithography process together with the recess 12 and the adhesive groove 13.
[0089]
In such a configuration, the element substrate 4 is bonded and fixed to the semiconductor laser substrate 5 in a state where the first contact surface 10 of the semiconductor laser substrate 5 and the second contact surface 11 of the element substrate 4 are in contact with each other. This can be done while maintaining. Since both the first contact surface 10 and the second contact surface 11 are smooth surfaces with high precision, the mounting of the diffraction grating 42 as an element on the semiconductor laser substrate 5 It is possible to remove the error factors such as the thickness of the bump and the adhesive, and to perform with high accuracy and a simple structure.
[0090]
Further, since the diffraction grating 42 is formed on the surface of the element substrate 4 facing the surface emitting laser 2, the diffraction grating 42 and the surface emitting laser are not affected by the thickness tolerance of the element substrate 4 when the diffraction grating 42 is mounted. 2 can be further reduced, and the mounting accuracy of the diffraction grating 42 with respect to the surface emitting laser 2 can be further increased.
[0091]
In this embodiment, as described in the first embodiment, a wafer-like laser substrate in which a plurality of surface emitting lasers 2 are provided in an array is formed, and a plurality of diffraction gratings are formed. 42 is formed in a wafer-like element substrate provided in an array, and these wafer-like laser substrate and wafer-like element substrate are bonded and fixed with an adhesive, and then separated by dicing, as shown in FIG. A plurality of composite optical elements 41 may be formed. Thereby, as compared with the case where the element substrate is bonded and fixed to the substrate of each surface emitting laser, the work of bonding and fixing the wafer-shaped laser substrate and the wafer-shaped element substrate performed when forming the plurality of composite optical elements 41 is performed. Since only one time is required, the manufacturing cost is reduced.
[0092]
A fifth embodiment of the present invention will be described with reference to FIGS. The composite optical element 51 of the present embodiment is obtained by bonding and fixing an element substrate 4 provided with a microlens 52 as an element to a semiconductor laser substrate 5 provided with a surface emitting laser 2. The microlens 52 is formed by forming a concave portion 53 on the quartz element substrate 4 and filling the concave portion 53 with a resin 54 which is a lens equivalent member. As the resin 54, a resin having a refractive index larger than that of quartz is used. The microlens 52 configured by filling the concave surface portion 53 with the resin 54 functions as a convex lens.
[0093]
The microlens 52 is disposed on the front side of the light emitted from the surface emitting laser 2 and is designed so that the diffused light emitted from the surface emitting laser 2 can be converted into parallel light. The concave surface portion 53 is formed by a photolithography process together with the concave portion 12 and the adhesive groove 13.
[0094]
In this configuration, the element substrate 4 is bonded and fixed to the semiconductor laser substrate 5 on which the surface emitting laser 2 is provided. The first contact surface 10 of the semiconductor laser substrate 5 and the second contact surface 11 of the element substrate 4 are used. It can carry out with maintaining the state which contacted. Since both the first abutment surface 10 and the second abutment surface 11 are smooth surfaces with high accuracy, the mounting of the microlens 52 as an element on the semiconductor laser substrate 5 can be performed with the insulating resin layer 7 or It is possible to remove the error factors such as the thickness of the bump and the adhesive, and to perform with high accuracy and a simple structure.
[0095]
FIG. 6 is an explanatory diagram illustrating the difference in incident angle between the case where the incident surface of the microlens is convex (a) and the case where it is flat (b). When the lens located opposite to the diffused light emitted from the surface emitting laser 2 has a convex shape as shown in (a), the incident angle (θ1) of the light with respect to the lens tangent becomes shallow and the reflectance is high. Become. Therefore, the lens shape facing the surface emitting laser 2 is preferably a concave shape. However, since the power is negative on the concave surface, the diffused light cannot be converted into parallel light. Therefore, a concave surface portion 53 is formed on the element substrate 4, and a lens equivalent member having a refractive index larger than that of the element substrate 4, for example, a resin 54 is filled in the concave surface portion 53 to form a microlens 52 that functionally becomes a convex lens. By forming, the optical incident angle (θ2) with respect to the lens tangent of the microlens 52 becomes deep, the reflectance becomes low, and the composite optical element 51 with little reflection and high light utilization efficiency can be obtained.
[0096]
Also in this embodiment, as described in the first embodiment, a wafer-like laser substrate in which a plurality of surface emitting lasers 2 are provided in an array is formed, and a plurality of microlenses is further formed. As shown in FIG. 5, a wafer-like element substrate 52 is provided in an array, and the wafer-like laser substrate and the wafer-like element substrate are bonded and fixed with an adhesive, and then separated by dicing. A plurality of composite optical elements 51 may be formed. As a result, as compared with the case where the element substrate is bonded and fixed to each surface emitting laser, the work of bonding and fixing the wafer-shaped laser substrate and the wafer-shaped element substrate in forming the plurality of composite optical elements 51 is one. The manufacturing cost can be reduced because it requires only one time.
[0097]
A sixth embodiment of the present invention will be described with reference to FIG. The composite optical element 61 of the present embodiment is an array of combinations of the surface emitting laser 2 and the microlens 32 described in the third embodiment (see FIG. 3). The composite optical element 61 includes a wafer-like laser substrate 62 that is a substrate on which a plurality of surface emitting lasers 2 are arranged in an array, and a wafer-like element substrate that is an element substrate on which a plurality of microlenses 32 are arranged in an array. It is formed by bonding and fixing 63.
[0098]
The wafer-like laser substrate 62 and the wafer-like element substrate 63 are bonded and fixed by exposing the epitaxial surface of the wafer-like laser substrate 62 as the first contact surface 10. This is performed by bringing the second contact surface 11 that is a polishing surface into contact with the second contact surface 11 and injecting the adhesive 14 into the adhesive groove 13 formed in the first contact surface 10.
[0099]
In such a configuration, in the composite optical element 61, the adjacent surface-emitting lasers 2 and the adjacent microlenses 32 can be positioned with high accuracy, so that the plurality of surface-emitting lasers 2 and the microlenses 32 are arranged in an array. Even in this case, the occurrence of crosstalk between adjacent surface emitting lasers 2 can be prevented.
[0100]
A seventh embodiment of the present invention will be described with reference to FIG. In the present embodiment, as described in the sixth embodiment (see FIG. 7), a wafer-like laser substrate 62, which is a substrate in which a plurality of surface emitting lasers 2 are arranged in an array, and a plurality of micro-lasers. A wafer-like element substrate 63 which is an element substrate in which lenses 32 are arranged in an array is bonded and fixed by an adhesive 14 injected into the adhesive groove 13. Thereafter, the wafer-like laser substrate 62 and the wafer-like element substrate 63 are diced at a predetermined dicing position, thereby forming a plurality of composite optical elements in which the microlens 32 and the surface emitting laser 2 are paired one by one. The
[0101]
An electrode groove 64 is formed on the substrate surface of the wafer-like element substrate 63 facing the wafer-like laser substrate 62. The electrode groove 64 is used when dicing the wafer-like laser substrate 62 and the wafer-like element substrate 63 which are bonded and fixed to produce a composite optical element having one surface emitting laser 2 and one microlens 32, respectively. In addition, it is formed at a position including a position where the dicing is performed.
[0102]
In such a configuration, the wafer-like element substrate 63 and the wafer-like laser substrate 62 that are bonded and fixed can be diced from the wafer-like element substrate 63 at a time. A is a dicing position at this time, and the electrode groove 64 is exposed by this dicing.
[0103]
A plurality of composite optical elements 1 each including one surface emitting laser 2 and a microlens 32 are formed by dicing at the dicing position A, and then the surface emitting laser is obtained by dicing the element substrate side at the position B. A deviation can be caused between the substrate end surface on the second side and the substrate end surface on the microlens 32 side, and wire bonding or the like can be performed at the portion where the deviation occurs to connect to the electrode of the surface emitting laser 2. When dicing at the position B, the dicing stop position may be within the height dimension of the electrode groove 64, and the wafer-like laser substrate 62 may be damaged during dicing without controlling the dicing stop position with high accuracy. Therefore, the workability of the dicing work is improved.
[0104]
An eighth embodiment of the present invention will be described with reference to FIGS. In the composite optical element 71 of this embodiment, an optical fiber 72 as a light transmission component is directly bonded to the element substrate 4 of the composite optical element described in the third embodiment (see FIG. 3). Yes.
[0105]
The optical fiber 72 is joined to the element substrate 4 by forming a fixed groove 73 in the element substrate 4 and inserting the tip of the optical fiber 72 into the fixed groove 73. The inner diameter dimension of the fixed groove 73 is set to be substantially the same as the outer diameter dimension of the optical fiber 72. The fixing groove 73 is formed by a photolithography process.
[0106]
A resin 74 is injected between the tip of the optical fiber 72 and the bottom surface of the fixed groove 73.
[0107]
FIG. 10 shows an outline of an optical transceiver 75 using a composite optical element 71 to which an optical fiber 72 is directly bonded. The optical transceiver 75 includes a composite optical element 71 to which an optical fiber 72 is directly bonded, an LSI 77 connected to the composite optical element 71 via an electrical wiring wire 76, and an electrical connector connected to the LSI 77 by an electrical wiring wire 76. 78, a submount 79 in which a V-groove for holding the optical fiber 72 is formed, a stem 80 on which an LSI 77 and the like are mounted, and the like. In the present embodiment, four optical fibers 72 are used, and the four composite optical elements 71 to which the optical fibers 72 are joined are attached to the submount substrate 16.
[0108]
In such a configuration, since the optical fiber 72 is directly bonded to the element substrate 4, the mounting accuracy of the optical fiber 72 with respect to the element substrate 4 is increased. In particular, in the optical axis direction, it is only necessary to press the optical fiber 72 and the element substrate 4, and high mounting accuracy can be realized at low cost.
[0109]
Further, since the distal end of the optical fiber 72 is inserted into the fixed groove 73, positional displacement in the direction orthogonal to the optical axis of the optical fiber 72 is prevented, and high mounting accuracy can be obtained at low cost in the direction orthogonal to the optical axis. Can do.
[0110]
When an air layer exists between the optical fiber 72 and the element substrate 4, reflection occurs at the end face of the optical fiber 72. However, in the present embodiment, since the resin 74 is injected between the front end portion of the optical fiber 72 and the bottom surface of the fixing groove 73, there is no air layer between the optical fiber 72 and the element substrate 4. The refractive index difference between the element substrate 4 and the optical fiber 72 is reduced and the reflectance is lowered, and the optical coupling efficiency between the element substrate 4 and the optical fiber 72 is increased.
[0111]
A ninth embodiment of the present invention will be described with reference to FIG. The basic structure of the optical composite element 81 of the present embodiment is the same as that of the eighth embodiment (see FIG. 9). A fixed groove 73 is formed in the element substrate 4, and the tip of the optical fiber 72 is formed in the fixed groove 73. Has been inserted.
[0112]
Further, a condensing lens 82 is provided at the center of the fixed groove 73. The condensing lens 82 has a function of condensing, on the optical fiber 72, the light that has been collimated by the microlens 32 on the surface emitting laser 2 side. The condensing lens 82 is also formed into an aspherical shape by a semiconductor process using a gray scale mask, like the microlens 32.
[0113]
A taper portion 83 whose diameter is increased outward is formed at the edge of the fixing groove 73. Furthermore, a tapered portion 84 that is reduced in diameter toward the distal end side is formed at the distal end portion of the optical fiber 72. The taper angles of the taper portion 83 and the taper portion 84 are set to substantially the same angle.
[0114]
In such a configuration, the light incident on the optical fiber 72 is collected by the condensing lens 82, so that even if the thickness of the element substrate 4 varies, a spot is surely formed on the end face of the optical fiber 72. It can be tied and the optical coupling efficiency is increased.
[0115]
Further, a taper portion 83 is formed at the edge of the fixing groove 73, and a taper portion 84 is formed at the tip of the optical fiber 72. The taper angles of the taper portions 83 and 84 are set to be approximately the same angle. When the tip of the optical fiber 72 is inserted into the groove 73, the tapered portion 83 and the tapered portion 84 are in surface contact, and the mounting state of the optical fiber 72 is more stable.
[0116]
【The invention's effect】
  According to the composite optical element of the first aspect of the present invention, the surface-emitting laser of the surface-emitting laser is maintained with the first contact surface of the surface-emitting laser and the second contact surface of the element substrate kept in contact with each other. The substrate and the element substrate can be fixed, so that the element can be mounted on the substrate of the surface emitting laser, such as the thickness of the insulating resin layer or the thickness of the adhesive covering the substrate surface of the substrate of the surface emitting laser. It is possible to remove the error factor with high accuracy and with a simple structure.In particular, the electrode groove is exposed by dicing after bonding the substrate having the surface emitting laser and the element substrate provided with the element, and wire bonding or the like can be performed with the electrode groove. When dicing so that the end surfaces of the substrate and the element substrate are shifted during dicing, the dicing stop position may be set within the height dimension of the electrode groove, and a highly accurate dicing stop position is required. Therefore, the workability of dicing work is improved.
[0117]
According to a second aspect of the present invention, in the composite optical element according to the first aspect, the first contact surface is an epitaxial surface and the second contact surface is a polished surface. Both the contact surface and the second contact surface are formed smoothly with high precision, the substrate of the fixed surface emitting laser and the element substrate are maintained in a high degree of parallelism, and the element to the substrate of the surface emitting laser is maintained. Mounting accuracy can be further increased.
[0118]
According to a third aspect of the present invention, in the composite optical element according to the first or second aspect, since the element is disposed on a surface side of the element substrate facing the surface emitting laser, the element and the surface light emission. With respect to the distance to the laser, the influence of the thickness tolerance of the element substrate can be eliminated, the tolerance of the distance between the element and the surface emitting laser can be reduced, and the mounting accuracy of the element with respect to the surface emitting laser can be increased.
[0119]
According to the invention of claim 4, in the composite optical element according to any one of claims 1 to 3, since the surface emitting laser and the element are arranged in an array, in this composite optical element, The surface-emitting laser can be mounted on the substrate easily and accurately, and even when these surface-emitting lasers and elements are arranged in an array, the light emitted from each surface-emitting laser is made parallel light. Thus, it is possible to prevent the occurrence of crosstalk of light emitted from the adjacent surface emitting laser.
[0121]
  Claim5According to the described invention, claims 1 to4In the composite optical element according to any one of the above, since the element is an electric wiring, the mounting accuracy of the electric wiring on the substrate of the surface emitting laser becomes high, and the surface emitting laser can be energized with high accuracy.
[0122]
  Claim6The invention described in claim 1 to claim 14In the composite optical element according to any one of the above, since the element is a microlens, the mounting accuracy of the microlens on the substrate of the surface emitting laser is increased, and the diffused light emitted from the surface emitting laser is highly accurately detected. It can be parallel light.
[0123]
  Claim7According to the described invention, the claims6In the described composite optical element, the microlens includes a concave surface portion formed on the element substrate and a lens equivalent member having a refractive index larger than that of the element substrate filled so as to form a convex lens in the concave surface portion. Therefore, the reflectance when the light emitted from the surface emitting laser hits the microlens can be kept low, and a composite optical element with high light utilization efficiency can be obtained.
[0124]
  Claim8According to the described invention, claims 1 to4In the composite optical element according to any one of the above, since the element is a diffraction grating, the mounting accuracy of the diffraction grating on the substrate of the surface-emitting laser is increased, and light emitted from the surface-emitting laser other than the optical axis It is possible to fly accurately in any direction.
[0125]
  Claim9According to the described invention, claims 1 to8In the composite optical element according to any one of the above, since the light transmission component is directly bonded to the element substrate, the manufacturing error included in the fixing member or the like as compared with the case where the light transmission component is fixed by the fixing member or the like. In particular, in the optical axis direction, since the light transmission component and the element substrate can be pressed against each other and mounted, high mounting accuracy can be realized at low cost.
[0126]
  Claim10According to the described invention, the claims9In the composite optical element described above, since the resin is interposed between the light transmission component and the element substrate, the resin is interposed between the light transmission component and the element substrate. The difference in refractive index between the transmission component and the reflectance is reduced, and the optical coupling efficiency between the element substrate and the light transmission component can be increased.
[0127]
  Claim11According to the described invention, the claims8Or9In the composite optical element described above, the light transmission component is an optical fiber, and a fixed groove into which the tip of the optical fiber is inserted is formed in the element substrate. Deviation can be prevented, and high mounting accuracy can be obtained at low cost.
[0128]
  Claim12According to the described invention, the claims11In the composite optical element described above, since the condensing lens is provided in the central portion of the fixed groove, the light incident on the optical fiber is collected by the condensing lens. Even if variations occur, spots can be reliably connected at the end face of the optical fiber, and the optical coupling efficiency can be increased.
[0129]
  Claim13According to the described invention, the claims11Or12In the above-described composite optical element, the edge of the fixed groove is formed with a tapered portion that expands outward, so that the optical fiber can be fixed to the fixed groove without providing play between the fixed groove and the optical fiber. Further, the taper portion functions to guide the optical fiber inserted into the fixed groove to the center of the fixed groove, so that the mounting accuracy of the optical fiber can be improved.
[0130]
  Claim14According to the described invention, the claims11Or13In the composite optical element according to any one of the above, since the tapered portion that is reduced in diameter toward the distal end side is formed at the distal end portion of the optical fiber, the optical fiber can be used without providing play between the fixed groove and the optical fiber. In addition, the taper can function to guide the optical fiber inserted into the fixed groove to the center of the fixed groove, so that the mounting accuracy of the optical fiber can be improved.
[0131]
  Claim15According to the described optical transceiver of the invention, the claims10Or14A low-cost optical transceiver can be provided by using the composite optical element in which the optical fibers according to any one of the above are directly joined.
[Brief description of the drawings]
FIG. 1 is a longitudinal front view showing a schematic structure of a composite optical element according to a first embodiment of the present invention.
FIG. 2 is a longitudinal front view showing a schematic structure of a composite optical element according to a second embodiment of the present invention.
FIG. 3 is a longitudinal front view showing a schematic structure of a composite optical element according to a third embodiment of the present invention.
FIG. 4 is a longitudinal front view showing a schematic structure of a composite optical element according to a fourth embodiment of the present invention.
FIG. 5 is a longitudinal front view showing a schematic structure of a composite optical element according to a fifth embodiment of the present invention.
FIG. 6 is an explanatory diagram for explaining a difference in incident angle between a case where the incident surface of the microlens is convex (a) and a case where it is flat (b).
FIG. 7 is a longitudinal front view showing a schematic structure of a composite optical element according to a sixth embodiment of the present invention.
FIG. 8 is a longitudinal front view showing a state before dicing in a manufacturing process of a composite optical element according to a seventh embodiment of the present invention.
FIG. 9 is a longitudinal front view showing a schematic structure of a composite optical element according to an eighth embodiment of the present invention.
FIG. 10 is a perspective view showing an outline of an optical transceiver using the composite optical element.
FIG. 11 is a longitudinal front view showing a schematic structure of a composite optical element according to a ninth embodiment of the present invention.
[Explanation of symbols]
1 Compound optical element
2 Surface emitting laser
3 elements, electrical wiring
4 Element substrate
5 Substrate
7 Insulating resin layer
10 Substrate surface, first contact surface, epitaxial surface
11 Substrate surface, second contact surface, polishing surface
13 Adhesive groove
14 Adhesive
21 Compound optical elements
22 elements, micro lens
31 Compound optical elements
32 elements, micro lens
41 Compound optical elements
42 elements, diffraction grating
51 Compound optical element
52 elements, microlens
53 Concave surface
54 Lens equivalent
61 Compound optical element
62 Substrate, wafer-like laser substrate
63 Element substrate, wafer-like element substrate
64 groove for electrode
71 Compound optical element
72 Optical transmission parts, optical fiber
73 Fixed groove
74 resin
77 LSI
78 Electrical connector
81 Compound optical element
82 Condensing lens
83 Taper
84 Taper

Claims (15)

In a composite optical element in which an element is mounted on a surface emitting laser substrate,
A first contact surface of the substrate;
A second contact surface which is a substrate surface of an element substrate provided with the element and is in contact with the first contact surface;
An adhesive groove formed in at least one of the contact surfaces of the first contact surface and the second contact surface;
An adhesive that is injected into the adhesive groove and positions the first contact surface and the second contact surface at a contact position to bond and fix the substrate and the element substrate;
I have a,
A composite optical element , wherein an electrode groove is formed on a surface of the element substrate facing the substrate, and dicing is performed at the position of the electrode groove .   The composite optical element according to claim 1, wherein the first contact surface is an epitaxial surface, and the second contact surface is a polished surface.   The composite optical element according to claim 1, wherein the element is disposed on a surface side of the element substrate facing the surface emitting laser.   4. The composite optical element according to claim 1, wherein the surface emitting laser and the element are arranged in an array. The element is composite optical element according to any one of claims 1 to 4, characterized in that an electric wiring. The element is composite optical element according to any one of claims 1 to 4, characterized in that a microlens. The microlens includes a concave portion formed on the element substrate and a lens-equivalent member having a refractive index larger than that of the element substrate filled to form a convex lens in the concave portion. 6. The composite optical element according to 6 . The element is composite optical element according to any one of claims 1 to 4, characterized in that a diffraction grating. Wherein the element substrate, the composite optical element of any one described in claims 1, characterized in that the optical transmitting component is joined directly 8. The composite optical element according to claim 9 , wherein a resin is interposed between the light transmission component and the element substrate. The light transmitting component is an optical fiber, the composite optical element according to claim 8, wherein the fixing groove tip of the optical fiber is inserted into the element substrate is formed. The compound optical element according to claim 11, wherein a condensing lens is provided at a central portion of the fixed groove. An edge of the fixing groove, the composite optical element according to claim 11 or 12, wherein the tapered portion whose diameter increases toward the outside is formed. The compound optical element according to any one of claims 11 to 13 , wherein a taper portion whose diameter is reduced toward the tip end side is formed at a tip end portion of the optical fiber. A composite optical element to which the optical fiber according to any one of claims 10 to 14 is directly bonded;
An LSI connected to the composite optical element;
An electrical connector connected to the LSI;
Having optical transceiver.

Images